On Fri, 22 Dec 2006, Peter Zijlstra wrote:
>
> fix page_mkclean_one()
>
> - add flush_cache_page() for all those virtual indexed cache
> architectures.
I think the flush_cache_page() should be after we've actually flushed it
from the TLB and re-inserted it (this is one reason why I did the
"ptep_exchange()" version of this). Otherwise somebody can still write to
the page _after_ the cache flush..
> - handle s390.
Yeah, that looks like the proper way to handle that.
That said, it looks like we still see corruption. You may not, but Martin
and Andrei still report problems, even with all the patches (including the
last one from Andrew that avoids "dirty" going negative under some
circumstances, and explains the "slow and/or never completed" case that
Gordon and Martin saw).
The good news is that I think the code now is cleaner and more
understandable. The bad news is that nothing we've ever tried seems to
have fixed the _problem_.
And I don't think it's page_mkclean(). Especially not since the ARM people
are seeing this under UP without PREEMPT. In that kind of schenario, the
only possible races tend to be from things that actually block:
"set_page_dirty()" (which blocks on IO in balancing), memory allocations,
and obviously doing actual IO.
And it's not a virtual cache problem, since others see it on x86.
Of course, since it's quite possibly two different issues, maybe the
virtual cache flush is required in order to force write-back to memory
(which in turn is required for the DMA for the actual write!). So the ARM
issue certainly could be due to the flush_cache_page() thing...
Linus
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to [email protected]
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
[Index of Archives]
[Kernel Newbies]
[Netfilter]
[Bugtraq]
[Photo]
[Stuff]
[Gimp]
[Yosemite News]
[MIPS Linux]
[ARM Linux]
[Linux Security]
[Linux RAID]
[Video 4 Linux]
[Linux for the blind]
[Linux Resources]
